简易版Http请求工具

简易版Http请求工具

这里的联网应用程序使用java.net包下的URL/HttpURLConnection类实现get/post请求

1、创建一个RUL对象

URL url = new URL(reqUrl);

2、获取URLConnection实例，与URL引用的远程对象的连接。

HttpURLConnection conn = (HttpURLConnection)url.openConnection();

3、HttpURLConnection打开指向此引用的资源的通信链接

conn.connect();

4、从此打开的连接读取的输入流。

conn.getInputStream()

5、处理输入流
根据业务处理输入流

GET请求

关键代码

public static String doGet(URL url, String encoding) throws IOException {
    BufferedReader reader = null;
    HttpURLConnection conn = null;
    try {
        conn = (HttpURLConnection)url.openConnection();
        setConnectionParameter("GET", conn);
        setHeader(encoding, conn);
        conn.connect();
        reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding));
        return getResult(reader);
    } catch (IOException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
    } finally {
        if (reader != null){
            reader.close();
        }
        if (conn != null){
            conn.disconnect();
        }
    }
}

POST请求

关键代码

public static String doPost(URL url, Map<String, String> params, String encoding) throws IOException {
    DataOutputStream out = null;
    BufferedReader reader = null;
    HttpURLConnection conn = null;
    try {
        conn = (HttpURLConnection)url.openConnection();
        setConnectionParameter("POST", conn);
        setHeader(encoding, conn);
        conn.connect();
        if ((null != params) && (!params.isEmpty())) {
            out = new DataOutputStream(conn.getOutputStream());
            String stringParams = buildParams(params);
            out.write(stringParams.getBytes());
            out.flush();
        }
        reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding));
        return getResult(reader);
    } catch (Exception e) {
        throw new RuntimeException(e);
    } finally {
        if (reader != null){
            reader.close();
        }
        if (out != null){
            out.close();
        }
        if (conn != null){
            conn.disconnect();
        }
    }
}

完整代码

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;

public class HttpUtils {

    private static final String CHARSET = "UTF-8";

    public static String doGet(String reqUrl) throws IOException {
        return doGet(reqUrl, CHARSET);
    }

    public static String doGet(String reqUrl, String encoding) throws IOException {
        URL url = new URL(reqUrl);
        return doGet(url, encoding);
    }

    public static String doGet(URL url, String encoding) throws IOException {
        BufferedReader reader = null;
        HttpURLConnection conn = null;
        try {
            conn = (HttpURLConnection)url.openConnection();
            setConnectionParameter("GET", conn);
            setHeader(encoding, conn);
            conn.connect();
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding));
            return getResult(reader);
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        } finally {
            if (reader != null){
                reader.close();
            }
            if (conn != null){
                conn.disconnect();
            }
        }
    }

    public static String doPost(String reqUrl, Map<String, String> params) throws IOException {
        return doPost(reqUrl, params, CHARSET);
    }

    public static String doPost(String reqUrl, Map<String, String> params, String encoding) throws IOException {
        URL url = new URL(reqUrl);
        return doPost(url, params, encoding);
    }

    public static String doPost(URL url, Map<String, String> params, String encoding) throws IOException {
        DataOutputStream out = null;
        BufferedReader reader = null;
        HttpURLConnection conn = null;
        try {
            conn = (HttpURLConnection)url.openConnection();
            setConnectionParameter("POST", conn);
            setHeader(encoding, conn);
            conn.connect();
            if ((null != params) && (!params.isEmpty())) {
                out = new DataOutputStream(conn.getOutputStream());
                String stringParams = buildParams(params);
                out.write(stringParams.getBytes());
                out.flush();
            }
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding));
            return getResult(reader);
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            if (reader != null){
                reader.close();
            }
            if (out != null){
                out.close();
            }
            if (conn != null){
                conn.disconnect();
            }
        }
    }

    /**
     * 设置连接参数
     * @param method
     * @param conn
     * @throws IOException
     */
    private static void setConnectionParameter(String method, HttpURLConnection conn) throws IOException {
        conn.setDoOutput(true);
        conn.setDoInput(true);
        conn.setInstanceFollowRedirects(true);
        conn.setConnectTimeout(1000*10);
        conn.setReadTimeout(1000*10);
        conn.setRequestMethod(method);
    }

    /**
     * 设置请求属性
     * @param encoding
     * @param conn
     */
    private static void setHeader(String encoding, HttpURLConnection conn) {
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("accept-language", "zh_CN");
        conn.setRequestProperty("Charset", encoding);
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        //伪装浏览器
        conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36");
    }

    private static String getResult(BufferedReader reader) throws IOException {
        StringBuffer buff = new StringBuffer();
        String line = reader.readLine();
        while (line != null) {
//            buff.append("\n"+ line);
            buff.append(line);
            line = reader.readLine();
        }
        String result = buff.toString();
        return result;
    }

    private static String buildParams(Map<String, String> params) {
        if (null == params || params.isEmpty()){
            return "";
        }
        StringBuilder sb = new StringBuilder();
        int i = 0;
        for (Map.Entry entry : params.entrySet()) {
            if (i > 0){
                sb.append("&");
            }
            sb.append((String)entry.getKey());
            sb.append("=");
            sb.append((String)entry.getValue());
            i++;
        }
        return sb.toString();
    }

}